cc'ing in Vitaly who knows about the hv stuff. * Antoine Damhet (antoine.dam...@blade-group.com) wrote: > Hi, > > We are experiencing timestamp rollbacks during live-migration of > Windows 10 guests with the following qemu configuration (linux 5.4.46 > and qemu master): > ``` > $ qemu-system-x86_64 -enable-kvm -cpu host,kvm=off,hv_time [...] > ```
How big a jump are you seeing, and how did you notice it in the guest? Dave > I have tracked the bug to the fact that `kvmclock` is not exposed and > disabled from qemu PoV but is in fact used by `hv-time` (in KVM). > > I think we should enable the `kvmclock` (qemu device) if `hv-time` is > present and add Hyper-V support for the `kvmclock_current_nsec` > function. > > I'm asking for advice because I am unsure this is the _right_ approach > and how to keep migration compatibility between qemu versions. > > Thank you all, > > -- > Antoine 'xdbob' Damhet -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
